The use of a hydrophobic adsorption medium for removing a dissolved compound from an aqueous solution is a well-known and relatively straight-forward process when a two-component mixture is being separated. Adsorption processes intended to selectively remove one component from a multi-component system could also be relatively uncomplicated if the adsorption medium were exclusively selective for one of the components. Unfortunately, this is seldom if ever the case and, if it is desired to remove a single compound from a complex mixture of chemical compounds in aqueous solution, such as aqueous food extracts, various new processing schemes must be developed and employed.
It has been found that when aqueous coffee extracts are contacted with presently available adsorption mediums capable of adsorbing caffeine numerous other compounds, most notably chlorogenic acid, are also adsorbed by the adsorbent such that caffeine constitutes only a minor amount of the total solids adsorbed. Such a process would be economically unattractive unless a technique were developed for recovering and adding-back a significant portion of the non-caffeine solids which would be lost if only classical adsorption procedures were employed.